Hovenia pubescens Sweet

Hovenia pubescens was first listed (though not described) by Robert Sweet in 1826, from a plant grown under glass in England (Sweet 1826), which had been introduced from Nepal in or before 1823. Sweet did not locate his specimen, but there is a temptation to associate his record with John Lindley’s reference (Lindley 1820) to a Hovenia grown at Cattley Close (now in north London), which had come from Nepal via the Calcutta Botanic Garden, but which was supposed to have been brought to Nepal in turn from China, and which Lindley considered very similar to his newly described H. acerba (Lindley 1820; Sengupta & Safui 1984). However, Sweet chose to place Lindley’s H. acerba in synonymy with Thunberg’s glabrous H. dulcis, and clearly felt that his pubescent, Nepalese plant was something different.

Today, the name Hovenia pubescens is used to describe a population of trees resembling H. acerba in their deeply forked style and the small, yellowish-brown (rather than blackish-brown) seed capsule, but distinguishable because of the soft hairs covering the style and the capsule at least; these plants are sympatric with H. acerba in parts of western China but extend westwards along the foothills of the Himalaya, and possibly further southwards into Indochina (Royal Botanic Gardens Kew 2022; Nesom 2023). The taxon was also described, from its native forests, as H. kiukiangensis by Shiu-ying Hu & W.C. Cheng in 1948, and many authorities, including Chen & Schirarend (2007), treat it as a variety (var. kiukiangensis) of H. acerba, a combination published by C.R. Wu in 1979 (Royal Botanic Gardens, Kew 2024). Hu and Cheng’s name relates to Kiukiang (Jiujiang) in Yunnan, not the city of the same name in Jiangxi, further east in China. Despite the specific name, H. pubescens is less hairy, particularly in terms of its foliage, than are some forms of H. tomentella.

Although there is no evidence that Sweet’s 1823 plant was ever tested out of doors in England, this nomenclatural history does make it possible that, of those few plants cultivated in Europe and North America as Hovenia acerba, some at least could really have represented H. pubescens. Careful study would have been needed to prove or disprove this hypothesis. The species’ hardiness, as listed above, is mere guesswork; its slightly more southerly distribution, relative to H. acerba, might imply that it is more tender.